The present invention relates to a tension indicator for screw connections.
Usually, where the tension of a screw connection must be within predeterminde limits, the connection is tightened by means of a key provided with a torque indicator or means to limit the torque to a maximum value. This tool serves therefor as the tension indicator.
In many cases this practice has proven to be satisfactory. However, there are certain drawbacks: There is no means to check the connection, once tightened, whether the applied tension was adequate or has remained, after a certain time of service, within the prescribed limits. Further, there are designs including more than one screw connection acting upon one and the same component such that tightening of one screw will affect the tension of one or more other screw connections because of tilting moments or the like.
It is a primary object of the invention to provide a tension indicator for screw connections permitting, at any time, whether there is adequate tension provided by the screw connection.